/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.hddz.comlib.ui.base.quicksearchbox;

import java.util.WeakHashMap;

import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.text.TextUtils;
import android.util.Log;

/**
 * Icon loader that caches the results of another icon loader.
 * 
 */
public class CachingIconLoader implements IconLoader
{
	private static final boolean								DBG	= false;
	private static final String									TAG	= "QSB.CachingIconLoader";
	private final IconLoader									mWrapped;
	
	//
	private final WeakHashMap<String, Drawable.ConstantState>	mIconCache;

	/**
	 * Creates a new caching icon loader.
	 * 
	 * @param wrapped
	 *            IconLoader whose results will be cached.
	 */
	public CachingIconLoader(IconLoader wrapped)
	{
		mWrapped = wrapped;
		mIconCache = new WeakHashMap<String, Drawable.ConstantState>();
	}

	public Drawable getIcon(String drawableId)
	{
		if (DBG)
			Log.d(TAG, "getIcon(" + drawableId + ")");
		if (TextUtils.isEmpty(drawableId) || "0".equals(drawableId))
		{
			return null;
		}
		Drawable drawable = checkIconCache(drawableId);
		if (drawable != null)
		{
			return drawable;
		}
		drawable = mWrapped.getIcon(drawableId);
		storeInIconCache(drawableId, drawable);
		return drawable;
	}

	public Uri getIconUri(String drawableId)
	{
		return mWrapped.getIconUri(drawableId);
	}

	private Drawable checkIconCache(String drawableId)
	{
		Drawable.ConstantState cached = mIconCache.get(drawableId);
		if (cached == null)
		{
			return null;
		}
		if (DBG)
			Log.d(TAG, "Found icon in cache: " + drawableId);
		return cached.newDrawable();
	}

	private void storeInIconCache(String resourceUri, Drawable drawable)
	{
		if (drawable != null)
		{
			mIconCache.put(resourceUri, drawable.getConstantState());
		}
	}
}
